Carburetor



April 26, 1932. w, C. CARTER 1,855,182

CARBURETOR Filed Oct. 3l, 1930 Inventor: Zl/z'lliam 0. Carer www..

Patented Apr; 26, 1932 WILLIAM c. CARTER, or I-LINT, MICHIGAN caanuamoa Application led October 31, 1930. Serial No. 492,395.

This invention relates to carburetors of the kind that are used for supplying fuel to internal combustion engines, and particularly, to carburetors of the type that are equipped with an air pump for creating a pressure in the fuel reservoir of the carburetor above the level of the fuel therein, so as to feed an accelerating charge to the fuel supplying device of the carburetor when the throttle valve 10 is actuated to accelerate the speed of the engine on which the carburetor is used.

One object of my invention is to provide a carburetor of the particular type mentioned, in which the fuel reservoir is provided with a relatively large air vent that normally maintains atmospheric pressure, or substantially atmospheric pressure, in said reservoir.

Another object is to provide a carburetor of the particular type mentioned, which is of such design that notwithstanding the fact that the air pump of the carburetor is of very small size, the pressure that is created in the fuel reservoir when the throttle valve is actuated to accelerate the engine is great enough to insure an accelerating charge being fed to the fuel supplying device of the carburetor.

Another object is to provide a carburetor of the particular type mentioned, which is of such design that it can be adjusted easily to change or vary the duration of the accelerating charge that is fed to the fuel supplying device.

Another object is to provide a carburetor of the particular type mentioned, which 1s of lvsuch design that the suction stroke of the piston of the air pump has absolutely no effect on the fuel in the fuel reservoir, and has no tendency to retard the flow of fuel from said reservoir to the fuel supplying def vlce.

And still another object of my invention is to provide a carburetorof the particular type mentioned, which is of such design that when an intermittently operating fuel pump is used to feed fuel to the fuel reservoir from a source of supply, the lpulsations of the pump will not produce pu sations in the stream of fuel being delivered to the fuel supplying device of the carburetor. Other o jects and desirable features of my invention will be hereinafter pointed out.

I have herein illustrated my invention embodied in a carburetor of the downdraft type, but I wish it to be understood that my invention is applicable to any kind of a carburetor that comprises a main passageway controlled by a throttle valve or similar device, and a fuel reservoir from which fuel is delivered to a nozzle or other fuel supplying device. i

The figure of the drawing is a vertical sectional View of a. carburetor embodying my present invention.

In the drawing the reference character A designates the main passageway of the carburetor, B designates the throttle valve, C designates an a1r control valve or choke arranged between the throttle valve and the air inlet of said main passageway, D designates a nozzle or other suitable fuel supplying device arranged in the main passageway, E designates a fuel reservoir such as a conventional lloat chamber provided with a float F that governs a valve G which controls the admission of liquid fuel to the reservoir E from a source of supply, H designates the fuel outlet of the reservoir E through which the fuel escapes into a fuel passageway I that leads to the fuel nozzle, and J designates a control valve for the fuel passageway I.

The carburetor is equipped with an air pump, designated as an entirety by the reference character K, that comprises a vertically-disposed cylinder 1 and a reciprocating iston 2 in said cylinder. Said piston is com ined with the throttle valve B in such a way that when the throttle valve is actuated to accelerate the speed of the engine, the piston 2 will be moved in a direction to compress air in the cylinder 1 of the'pump. I have herein illustrated the ypiston of the pump asbeing connected by means of a link 3 with an arm 4 attached to the shaft 5 of the throttle valve, but I Wish it to be under stood that it is immaterial what means is employed for causing the piston of the air pump K to act in unison with the throttle valve of the carburetor. The cylinder 1 of the air pump is herein illustrated as being arranged on the outside of the tubular casting that constitutes the main passageway of the carburetor, and is connected to said casting by fastening devices 6 which pass through lugs 7 on the cylinder, but the particular location or arrangement of the pump cyllnder is also immaterial.

A discharge pipe 8 leads from the upper end of the cylinder of the air pump K to a device, which, for convenience,I have termed an air injector and which I have designated' by the reference character L. Said air injector is composed of a nozzle 9 provided with a restricted orifice, and a member 10 arranged in an opening 11 in the top wall 12 of the fuel reservoir E and provided with an air vent 18 into which the nozzle 9 discharges. Preferably, the air vent 13 is provided with branch ports 14 that terminate in the outer surface of the member 10, and which are arranged in such relationship with the nozzle 9 that the jet of air which emerges from the restricted orifice of said nozzle will cause a relatively large volume of air to be drawn inwardly through the air ports 14 and carried into the fuel reservoir E above the level of the fuel therein. As shown in the drawing, the air vent 13 has a restriction la located beyond the end of the nozzle 9. Preferably, the nozzle 9 is rigidly connected to the discharge pipe 8 leading from the air pump and is fitted in a bore formed in the upper end portion of the air vent member 10. The air pump K is provided with an adjustable valve 15 for varying or regulating the flow of air from .the pump to the air injector L.

Due to the fact that the air vent in the top of the fuel reservoir E is of relatively large area, the space in the upper portion of said fuel reservoir will be normally maintained at atmospheric pressure, or substantially atmospheric pressure. However, when the throttle valve B is actuated to accelerate the speed of the engine, the piston 2 of the air pump K will compress air in the cylinder 1 of said pump and cause. a jet of air under a high pressure to emerge from the restricted orifice of the nozzle 9 attached to the discharge pipe of the pump. The velocity of the air escaping fromI said nozzle downwardly through the restriction 13 of the air vent 13, creates a vacuum on the ports 14, with the result that a large volume of air will be drawn into the fuel reservoir E, thereby instantly creating a pressure in said reservoir that causes an accelerating charge of fuel to be fed to the nozzle D. As soon as the air jet from the nozzle 9 ceases the inflow of air into the fuel reservoir ceases, with the result that atmospheric pressure, or substantially atmospheric pressure will be re-established in the fuel reservoir.

By changing the position of the valve 15 of the air pump the duration of the acceleratsirable that an accelerating charge of relatively small volume but of long duration be delivered to the fuel supplying device D of the carburetor, the valve 15 is set so as to restrict the size of the orifice controlled by said valve, and thus cause the compressed air to escape from` the cylinder of the pump at a slower rate, with the result that the velocity of the air emerging from the nozzle 9 of the air injector will be diminished, but the period which the air jet continues to flow from the nozzle will be prolonged.

ln prior carburetors of this general typethe discharge pipe from the air pump is directly connected with the interior of the fuel reservoir, and no air other than that compressed in the cylinder of the pump is admitted to the fuel reservoir during the compression stroke of the pump piston. This necessitates the use of a relatively large air pump, and it also makes it necessary to provide. the fuel reservoir with a relatively small air vent in order to insure the pressure building utp quickly in the fuel reservoir when the throttle is actuated to accelerate the speed of the engine. A large air pump is objectionable on account of its size, and a small air vent for the fuel reservoir is objectionable, particularly if an intermittently operating fuel pump is employed to feed fuel to the fuel reservoir from a source of supply, due to the fact that the pulsations of the fuel pump have a tendency to produce pulsations in the stream of fuel being delivered to the fuel supplying device, thereby causing a vari ation in the discharge of the fuel from the devices which supply fuel to themain passageway of the carburetor. My improved carburetor has neither of these objectionable characteristics. In the first place, the pressure relied upon to feed an acelerating charge to the fuel supplying device of the carburetor is produced, not solely by the air that is compressed in the cylinder of the air pump, but on the contrary, is produced by utilizing a small jet of high pressure air traveling at a great velocity to draw a large volume of air into the fuel reservoir above the level of the fuel therein. Hence, it is commercially practicable to equip the carburetor with a very small air pump. In the second place, the air vent of the fuel reservoir of my carburetor is of suflicient area to normally maintain atmospheric pressure or substantially atmospheric pressure inthe upper portion of the uel reservoir. Hence, if an intermittently operating pump is used to feed fuel into the fuel reservoir of the carburetor, the ulsations of the fuel pump will have no e ect on the fuel supplying device of the carburetor, due, of course, yto the fact that the fuel pump ldischarges into a space that is adequately reservoir is exerted on the fuel in the reservoir and has a tendency to retard the free flow of the fuel to the fuel supplying device of the carburetor. In order to overcome this inherent objection or defect of prior carburetors I connect the discharge pipe of the pump of my carburetor to a nozzle that discharges into an air vent, and I employ an air pump that is equipped with an inlet valve or similar device that opens automatically during the suction stroke of the pump piston and admits air directly to the cylinder of the pump. Various types and kinds of devices may be used to admit air to the cylinder of the pump during the suction stroke of the piston, but I prefer to use an air pump whose piston l is provided with a flexible packing 2, preferably combined with a spring or other suitable expanding device 2b, which packing, during the suction stroke or downward stroke of the piston, will flex in a direction to permit air to flow into the cylinder l between the side wall of same and the peripheral edge of the piston. During the compression stroke of the piston the pressure that is created in the Cylinder holds the packing 2 tightly against the side wall of the piston and effectively prevents the air from escaping past the piston.

Having thus described my invention, what I claim as new and desire to secure by Letters Patent is:

1. A carburetor provided with a fuel reservoir. an air injector for creating pressure in said reservoir above the 1evel of the fuel therein, and means for causing sail injector to act when the throttle valve of he carbu- 'retor is actuated to accelerate the speedv of the engine.

2. A carburetor provided with a fuel reservoir, a throttle valve. an air pump arranged f so as to compress air when said throttle valve is moved in a direction to accelerate the speed of the engine, a restricted orifice through which the air discharges from said pump, and means for utilizing the jet of air emerging from said restricted orifice to cause air to be drawn into said reservoir above the level of the fuel therein so as to create a pressure in the upper portion of the reservoir.

3. In a carburetor, the combination of a fuel reservoir. an air pump, a nozzle adapted to receive air from said pump, and means for utilizing the jet of air emerging from said nozzle to draw a relatively large' volume of air into the reservoir above the level of the fuel therein so as to create a pressure in the reservoir.

4. A carburetor provided with a fuel reservoir, an air vent for said reservoir, a throttle valve, and means whereby actuation of said throttle valve to accelerate the speed of the engine will cause a jet of air to How through said air vent in a direction to draw air inwardly through said vent and thus cre'- ate a pressure in the fuel reservoir above the level of the fuel therein.

5. A carburetor provided with a throttle valve, a fuel supplying device, a fuel re'servoir from which fuel is delivered to said fuel suplying device, an air pump combined with said throttle valve so as to compress air when said throttle valve' is actuated to accelerate the speed of the engine, and an air injector adapted to receive air from said pump for creating pressure in said reservoir so as to feed an accelerating charge to said to accelerate the speed of the engine, an air vent that normally establishes direct communication between 'the atmosphere and the space in said reservoir above the level of the fuel therein, a. discharge nozzle for said air pump combined with said air vent so as to cause air to be drawn inwardly through said vent when a jet of air emerges from said nozzle, and an inlet valve for the pump that opens and permits air to pass into the cylinder of the pump directly from the atmosphere during the suction stroke ofthe pump piston. a

9. A carburetor provided with a fuel reservoir, a fuel supplying device to which fuel is delivered from said reservoir, a throttle valve, an air injector that normally acts as an air vent for said fuel reservoir, an air pump operatively connected with said throttle valve for supplying air to said air injector when the throttle valve is actuated to accelerate the engine, whereby pressure will -be created in said reservoir to feed an accelerating charge to the fuel supplying device, and means for enabling the duration of said accelerating charge to be varied.

10. A carburetor provided with a fuel reservoir, a throttle valve, an air pump provided With a piston that is operatively connected with said throttle valve, a packing on said piston that is adapted to Hex in a direction to permit air to enter said cylinder during the suction stroke of the piston, a nozzle through which a jet of air emerges during the compression stroke of said piston, and an air passageway at the upper end of said fuel reservoir arranged to receive the jet of air from said nozzle and provided with ports through which air is drawn into said reservoir by the vacuum exerted on said ports by said jet of air.

WILLIAM C. CARTER. 

